A few more for the rude angler list:

6. Anglers that float by you and drop anchor just downstream of you in a hole you happen to be plugging.
7. Anglers that cast near your line while you're playing a fish.
8. Anglers that croud in on your hole after they see you've landed a fish.
9. Anglers that take 20 minutes to get their rig out of the boat launch, making everyone wait while they take care of every last detail before they pull out.
10. A high percentage of the drift boaters fishing the Humptulips in the fall.